Bee safety and insect control

Neonicotinoid pesticides have become a hot button issue over the last few years, and have become the most visible scapegoat in the declining honeybee population.

Over the past two years, more than 110 garden retailers, nurseries and landscaping companies, including the two largest home improvement retailers in the world, Home Depot and Lowe’s, have taken steps to eliminate neonicotinoids from the plants they grow and sell.

AmericanHort and the Horticultural Research Institute, in partnership with the Society of American Florists created the Bee and Pollinator Stewardship Initiative taskforce to look deeper into this issue. The taskforce is composed of horticultural professionals and supported by research scientists. It’s their view that pesticides may play some role in the concerns about pollinator health but are likely to be one relatively small factor in a complex array of challenges.

Still, retailers are concerned. And the pressure they’ve received from concerned consumers has been redirected to growers, who have been forced to find other options.

“They’re good molecules; they’re systemic,” says Doug VanGundy, vice president of research and development for Central Life Sciences. “But the furor of bee safety has caused a lot of consumer pressure. So they have had to switch to other alternatives.”

For nursery operators seeking effective control of harmful insects without posing a risk to bees, Mavrik Aquaflow® Insecticide/Miticide provides control of a broad spectrum of insects and mites, without the concern of dried residue harming honeybees. This is supported by a Washington State University study that concluded that honeybees exposed to the residue of tau-fluvalinate had a survival rate of 97 percent after three hours, 96 percent after eight hours and 96 percent after 24 hours.

Nurseries should be aware that wet residues can still be harmful. For that reason, it’s important to carefully consider the timing of your spray.

“Applications should be made in times when the bee is not foraging,” VanGundy says. “In the late afternoon to early evening and early morning hours are the best times to apply if you’re concerned with bee safety. But after the residue dries, there is no issue. You can control your pests without harming the bees.”

As a pyrethroid class of insecticide, Mavrik Aquaflow® Insecticide/Miticide has a very broad label that includes aphids, whiteflies, thrips, mites, fungus gnats and even some perimeter pests like cockroaches.

“It covers the whole gamut of any problem a grower would have in a greenhouse,” VanGundy says.

Growers coming to Mavrik Aquaflow® Insecticide/Miticide from neonics should be aware of some differences.

Most neonics are systemic, which means they are applied in soil and move through the plant. But that means you’ve got to treat each plant, whether it needs it or not. Mavrik Aquaflow® Insecticide/Miticide is generally applied as a broadcast application. It can also be used with electrostatic sprayers, but it can be used in a handheld pump up sprayer to a large power sprayer, depending on how the grower wants to treat his greenhouse and on the type and severity of the pest problems. Generally, it can be applied more flexibly.

“If you have a corner of a greenhouse or a tray that is just starting to feel pressure, you can treat that without having to treat the whole greenhouse,” VanGundy says.

Also, as a water-based formula with low phyto-toxicity, Mavrik Aquaflow® Insecticide/Miticide is easy on plants. Its residual is shorter than a neonic, so it doesn’t stay around in the environment as long – which can be good or bad, depending on your point of view.

“Sometimes you don’t need that; other times you do,” VanGundy says. “It just depends on the pest pressure that you get.”

Choosing to administer a bee-friendly pesticide like Mavrik Aquaflow® Insecticide/Miticide may be the single greatest factor in limiting an operation’s impact on honeybees, but there are a number of steps operators can take to protect honeybees on a nursery.

Implement a comprehensive Integrated Pest Management (IPM) program to achieve the most efficient control of insects and reduce the reliance on pesticides. This includes cultural practices and sanitation efforts to limit conditions on a nursery that make it possible for pests to thrive. Efforts such as strategic plant placement, proactive weeding and ensuring the use of pest-free planting stock can all limit the proliferation of damaging insects.

“Even making a greenhouse tighter, making sure all the plastic and netting is tight to reduce the bugs that can get in,” VanGundy says. “Then, introduce biological control.”

Nursery operators can rely on beneficial insects that eat more harmful species to provide some naturally occurring control.

Another important component of an IPM program is regular monitoring of plants and recordkeeping. This will help operators identify insect problems quicker and know precisely where to target pesticide applications when they become necessary.

“In the greenhouse market a lot of people use yellow sticky cards placed on beds in various locations,” VanGundy says. “They can monitor where pest pressure is starting to build. In the corner of the greenhouse, by the door, or a fan, etc. When they start seeing the pest increase, it might be time to consider making an application.”

It is also recommended that operators establish a threshold for treatment – the point at which the anticipated economic damage to plants warrants pesticide application. This will allow operators to more strategically and judiciously apply pesticides rather than relying on a predetermined schedule.

Plant bee-friendly flowers near the nursery that can serve as a source of food. These flowers should be excluded from pesticide applications.

For more: www.centralgrower.com

Photo: Adobe Stock